JP2018143427A - Ophthalmologic apparatus, and control method and program of apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic apparatus, and a control method and a program of the apparatus for acquiring information that can be used for disease diagnosis on an eye to be examined.SOLUTION: An image area 600 including a blood vessel merging part where at least two blood vessels 310 and 320 join together and become one blood vessel 330 is extracted from blood vessel-containing images including a blood vessel of an eye to be examined; an image related to the image area 600 is analyzed and laminar flow information (e.g., information on the length 610 of the laminar flow, information on a laminar flow ratio of the width 621 of the laminar flow to the width 622 of the laminar flow, comparison information in which a blood vessel diameter ratio of a blood vessel diameter 623 to a blood vessel diameter 624 is compared to the laminar flow ratio) on a laminar flow of blood flowing in from the blood vessels 310 and 320 respectively in the blood vessel 330 is acquired; and control to display the laminar flow information is executed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an ophthalmologic apparatus for generating a blood vessel-containing image including a blood vessel of a subject eye, a method for controlling an apparatus for generating a blood vessel-containing image of a subject including a subject eye, and a program for causing a computer to execute the control method It is about.

  In recent years, an optical coherence tomography (hereinafter referred to as “OCT”) apparatus using interference by low-coherence light has been put into practical use as an ophthalmic apparatus for ophthalmic examination. For example, this OCT apparatus can depict a three-dimensional structure of the retina of the eye to be examined. In recent years, the OCT apparatus is not only based on the retinal structure, but also based on OCT Angiography (OCT Angiography) technology that renders retinal blood vessels non-invasively using signal changes between successively acquired tomographic images. It has been developed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2006-209200

  Recent research results discuss the usefulness of OCT angiography. In particular, OCT angiography in which the vascular state is visualized is effective in diagnosing eye diseases such as age-related macular degeneration and diabetic retinopathy. In this regard, the technique of Patent Document 1 is a technique for imaging blood vessels with high accuracy, and has not been considered until providing information that can be used for disease diagnosis of an eye to be examined using an OCT angiography image. It was.

  The present invention has been made in view of such problems, and an object thereof is to provide information that can be used for disease diagnosis of an eye to be examined.

The ophthalmologic apparatus of the present invention includes an image generation unit that generates a blood vessel-containing image including a blood vessel of a subject eye, and an image including a blood vessel merging portion in which at least two blood vessels merge from the blood vessel-containing image to form one blood vessel Extracting means for extracting a region; analyzing means for analyzing an image relating to the image region; and obtaining laminar flow information relating to laminar flow of blood flowing from each of the two blood vessels in the one blood vessel; Display control means for performing control to display the laminar flow information on the display unit.
The present invention also includes a method for controlling an apparatus including the above-described ophthalmologic apparatus, and a program for causing a computer to execute the control method.

  ADVANTAGE OF THE INVENTION According to this invention, the information which can be used for the disease diagnosis of a to-be-tested eye can be provided.

It is a figure which shows an example of schematic structure of the ophthalmologic apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the image area extraction process by the extraction means of FIG. It is a figure which shows an example of the OCTA image which concerns on the blood vessel merge part containing image area | region produced | generated by the production | generation means of FIG. It is a figure which shows an example of the brightness | luminance profile acquired by the analysis means of FIG. It is a flowchart which shows an example of the process sequence in the control method of the ophthalmologic apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the laminar flow information obtained by the analysis process of step S108 of FIG. It is a flowchart which shows an example of the detailed process sequence which concerns on the aspect 1 in the analysis process of FIG.5 S108. It is a flowchart which shows an example of the detailed process sequence which concerns on aspect 2 in the analysis process of FIG.5 S108. It is a figure which shows embodiment of this invention and shows the example which applied the fundus image obtained by the fluorescence fundus imaging method as the blood vessel containing image including the blood vessel of the eye to be examined.

  Hereinafter, embodiments (embodiments) for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a schematic configuration of an ophthalmologic apparatus 100 according to an embodiment of the present invention. As an ophthalmic apparatus 100 according to the present embodiment, an example in which an SS (Swept source) -OCT apparatus is applied will be described. However, the present invention is not limited to this. For example, as the ophthalmic apparatus 100 according to the present embodiment, it is also included in the present invention to apply another type of OCT apparatus, and also to apply an ophthalmic apparatus other than the OCT apparatus.

  As shown in FIG. 1, the ophthalmologic apparatus 100 includes a wavelength swept light source 110, an optical signal branching / multiplexing unit 120, an interference light detection unit 130, a computer 140, a measurement arm 150, a reference arm 160, and a display unit 170. Configured. Here, the computer 140 has a hardware configuration including, for example, a central processing unit (CPU) and a storage device. In this case, the storage device includes, for example, a memory (RAM and ROM) and a mass storage device (HDD). Further, a part or all of the storage device may be provided outside the computer 140.

  The wavelength swept light source 110 emits light having a wavelength of 980 nm to 1100 nm, for example, at a frequency of 100 kHz (A scan rate) based on the control of the computer 140. Here, the wavelength and frequency are examples, and the present embodiment is not limited to the values described above. Similarly, in the following description, the described numerical values are merely examples, and the present embodiment is not limited to the described numerical values. In the present embodiment, an example in which the fundus oculi Ef of the eye E to be examined is applied as an imaging target will be described. However, the present invention is not limited to this example. It is also included in the present invention that the eye part) is an object to be imaged.

  The optical signal branching / multiplexing unit 120 includes a coupler 121 and a coupler 122 as shown in FIG. First, the coupler 121 is a branching member that branches light emitted from the wavelength swept light source 110 into irradiation light for irradiating the fundus oculi Ef of the eye E to be examined and reference light. Irradiation light is applied to the eye E through the measurement arm 150. More specifically, the irradiation light incident on the measurement arm 150 is adjusted in the polarization state by the polarization controller 151 and then emitted from the collimator 152 as spatial light. Thereafter, the irradiation light is applied to the fundus oculi Ef of the eye E through the X-axis scanner 153, the Y-axis scanner 154, and the focus lens 155. The X-axis scanner 153 and the Y-axis scanner 154 are scanning members having a function of scanning the fundus oculi Ef with irradiation light. By this scanning member, the irradiation position of the irradiation light to the fundus oculi Ef is changed. Here, acquiring information in the depth direction (depth direction) of one point of the eye E is referred to as an A scan. Also, acquiring a two-dimensional tomographic image along a direction orthogonal to the A scan is B scanning, and further acquiring a two-dimensional tomographic image along a direction perpendicular to the two-dimensional tomographic image of B scanning. This is called scanning.

  Note that each of the X-axis scanner 153 and the Y-axis scanner 154 is configured by mirrors arranged so that the rotation axes are orthogonal to each other. The X-axis scanner 153 performs scanning in the X-axis direction, and the Y-axis scanner 154 performs scanning in the Y-axis direction. The X-axis direction and the Y-axis direction are directions perpendicular to the eye axis direction of the eyeball and perpendicular to each other. Further, the line scanning direction such as B scan and C scan may not coincide with the X axis direction or the Y axis direction. For this reason, the line scanning directions of the B scan and the C scan can be appropriately determined according to a two-dimensional tomographic image or a three-dimensional tomographic image to be photographed.

  The reflected light from the fundus oculi Ef is incident again on the coupler 122 through the coupler 121 via the same path such as the focus lens 155 again. Note that by measuring with the shutter 156 closed, the reflected light from the eye E can be cut and the background (noise floor) can be measured.

  On the other hand, the reference light enters the coupler 122 via the reference arm 160. More specifically, the reference light that has entered the reference arm 160 is adjusted in polarization state by the polarization controller 161 and then emitted from the collimator 162 as spatial light. Thereafter, the reference light passes through the dispersion compensation glass 163, the optical path length adjustment optical system 164, and the dispersion adjustment prism pair 165, enters the optical fiber via the collimator 166, exits from the reference arm 160, and enters the coupler 122.

  In the coupler 122, the return light of the measurement light from the eye E through the measurement arm 150 interferes with the reference light through the reference arm 160. Then, the interference light detection unit 130 detects the interference light. The interference light detection unit 130 includes a differential detector 131 and an A / D converter 132. In the interference light detecting unit 130, first, the interference light demultiplexed by the coupler 122 is detected by the differential detector 131. Then, the OCT interference signal converted into an electrical signal by the differential detector 131 (hereinafter, simply referred to as “interference signal”) is converted into a digital signal by the A / D converter 132. Here, the sampling of the interference light of the differential detector 131 is performed at equal wave number intervals based on the k clock signal transmitted from the clock generator incorporated in the wavelength swept light source 110. The digital signal output from the A / D converter 132 is sent to the computer 140. Thereafter, the computer 140 performs signal processing on the interference signal converted into the digital signal, and generates an OCT angiography image (hereinafter referred to as “OCTA image”) by calculation.

  The CPU included in the computer 140 executes various processes. Specifically, the CPU of the computer 140 functions as the generation unit 141, the extraction unit 142, the analysis unit 143, the storage unit 144, and the display control unit 145 by executing a program stored in the storage device of the computer 140. Note that the computer 140 may include one or more CPUs and storage devices. That is, at least one processing device (CPU) and at least one storage device (ROM or RAM, etc.) are connected, and at least one processing device executes a program stored in at least one storage device. In this case, the computer 140 functions as each of the means 141 to 145 described above.

  Hereinafter, the generation unit 141, the extraction unit 142, the analysis unit 143, the storage unit 144, and the display control unit 145, which are functional configurations of the computer 140, will be described.

  The generation unit 141 outputs a digital signal output from the A / D converter 132 (a digital interference signal based on interference light between the return light from the eye E and the reference light of the measurement light scanned with respect to the eye E). ) To generate an OCTA image. Here, the OCTA image corresponds to a blood vessel-containing image including blood vessels of the eye E (specifically, in the present embodiment, the fundus oculi Ef). Hereinafter, an example of a method for generating an OCTA image by the generating unit 141 will be described.

  First, the generation unit 141 acquires a tomographic image by performing Fourier transform on the interference signal acquired from the A / D converter 132. Specifically, the generation unit 141 obtains an OCT complex signal having a phase and an amplitude by applying a fast Fourier transform (FFT) to the interference signal. Note that the maximum entropy method may be used as the frequency analysis. Further, the generation unit 141 obtains a tomographic image indicating Intensity (hereinafter sometimes simply referred to as “tomographic image”) by squaring the absolute value of the OCT complex signal and calculating the signal intensity (Intensity). . This tomographic image corresponds to an example of tomographic image data indicating a tomographic image of the fundus oculi Ef of the eye E to be examined. That is, when the measurement light is scanned a plurality of times at substantially the same position of the fundus oculi Ef of the eye E, the generation unit 141 acquires a plurality of tomographic image data indicating the tomograms at substantially the same position of the subject. Note that the plurality of tomographic image data is data acquired by measuring light scanned at different timings.

  The generation unit 141 also functions as a unit that controls the X-axis scanner 153 and the Y-axis scanner 154.

  Subsequently, the generation unit 141 aligns a plurality of tomographic images. In the present embodiment, the generation unit 141 performs alignment of a plurality of tomographic images obtained by scanning approximately the same position of the fundus oculi Ef of the eye E with the measurement light a plurality of times. More specifically, the generation unit 141 aligns a plurality of tomographic image data before calculating a motion contrast value.

  Position alignment of tomographic images can be realized by various known methods. For example, the generation unit 141 aligns a plurality of tomographic images so that the correlation between the tomographic images is maximized. If the subject is not a specimen that moves like an eye, this alignment process is not necessary. Further, even if the subject is an eye, if the tracking performance is high, this alignment process is not necessary. That is, alignment of tomographic images by the generation unit 141 is not essential.

  Subsequently, the generation unit 141 calculates a motion contrast feature amount (hereinafter, also referred to as “motion contrast value”). Here, the motion contrast is a contrast between a flowing tissue (for example, blood) and a non-flowing tissue in the subject tissue, and a feature amount expressing the motion contrast is defined as a motion contrast feature amount.

  The motion contrast feature amount is calculated based on a change in data between a plurality of tomographic images obtained by scanning the substantially same position with the measurement light a plurality of times. For example, the generation unit 141 calculates a variance of signal intensity (luminance) of a plurality of aligned tomographic images as a motion contrast feature amount. More specifically, the generating unit 141 calculates the variance of the signal intensity at each corresponding position of the aligned tomographic images as a motion contrast feature amount. For example, since the signal intensity of an image corresponding to a blood vessel at a predetermined time and the signal intensity of an image corresponding to a blood vessel at a time different from the predetermined time vary depending on blood flow, the variance value of the portion corresponding to the blood vessel is blood flow The value is larger than the variance value of the part where there is no flow. That is, the motion contrast value is a value that increases as the change in the subject between a plurality of tomographic image data increases. Therefore, it is possible to express motion contrast by generating an image based on this variance value. Note that the motion contrast feature amount is not limited to the variance value, and may be any of a standard deviation, a difference value, a non-correlation value, and a correlation value, for example. The generation unit 141 uses signal intensity dispersion or the like, but may calculate motion contrast feature amounts using phase dispersion or the like.

  Subsequently, the generation unit 141 generates an averaged image by calculating an average value of the plurality of aligned tomographic images. This averaged image is a tomographic image in which the signal intensities of a plurality of tomographic images are averaged. This averaged image may be referred to as an intensity averaged image. The generation unit 141 compares the signal strength of the averaged image with a threshold value. When the signal intensity at the predetermined position of the averaged image is lower than the threshold value, the generation unit 141 uses the motion contrast feature quantity obtained based on the variance corresponding to the predetermined position of the averaged image as the feature quantity indicating the blood vessel. Use a different value. For example, when the signal strength of the averaged image is lower than the threshold value, the generation unit 141 sets the motion contrast feature amount obtained based on the variance or the like to 0. That is, the generation unit 141 sets the motion contrast value when the representative value indicating the signal strength is lower than the threshold value to be lower than the motion contrast value when the representative value indicating the signal strength is higher than the threshold value. Note that the generation unit 141 may compare the signal intensity of the averaged image with a threshold value before calculating the variance of the signal intensity of the plurality of tomographic images as the motion contrast feature amount. For example, the generation unit 141 calculates the motion contrast feature amount as 0 when the signal strength of the averaged image is lower than the threshold value, and when the signal strength of the averaged image is higher than the threshold value, Is calculated as a motion contrast feature amount.

  Note that the motion contrast feature amount may not be completely zero but may be a value near zero. On the other hand, when the signal strength of the averaged image is higher than the threshold value, the generating unit 141 maintains the motion contrast feature amount obtained based on the variance or the like. That is, the generation unit 141 calculates a motion contrast value based on a plurality of tomographic image data, and calculates the motion contrast value again based on the comparison result between the representative value indicating the signal intensity and the threshold value.

  In addition, although the signal intensity (average value of signal intensity) of the averaged image was used as a comparison target with the threshold value, representative values such as a maximum value, a minimum value, and a median value of the signal intensity at corresponding positions of a plurality of tomographic images. It is good also as using. Further, instead of comparing the signal intensity obtained from a plurality of tomographic images with a threshold value, the generation unit 141 may compare the signal intensity of one tomographic image with the threshold value to control the motion contrast feature amount. Good.

  As described above, the generation unit 141 calculates the motion contrast value based on the comparison result between the representative value of the plurality of tomographic image data and the plurality of tomographic image data indicating the signal intensity and the threshold value.

  Subsequently, the generation unit 141 generates an OCTA image based on the motion contrast feature amount. The OCTA image is an image of the motion feature amount calculated by the generation unit 141. For example, the larger the motion contrast feature amount, the higher the luminance, and the lower the motion contrast feature amount, the lower the luminance. Here, in the present embodiment, the portion with high luminance is a portion corresponding to a blood vessel. Note that the luminance may be lowered as the motion contrast feature amount is larger, and the luminance may be increased as the motion contrast feature amount is lower. This OCTA image may be referred to as a motion contrast image. That is, the generation unit 141 generates a motion contrast image of the subject based on the motion contrast value as the OCTA image.

  The generation unit 141 can generate a three-dimensional OCTA image when a three-dimensional motion contrast feature amount (three-dimensional data) is calculated from the three-dimensional tomographic image data. The generation unit 141 can also generate a two-dimensional OCTA image that is projected or accumulated in a depth range in an arbitrary retinal direction of the three-dimensional OCTA image. That is, the generation unit 141 can generate a two-dimensional motion contrast image by projecting or integrating a predetermined range of motion contrast values in the depth direction of the subject as the OCTA image.

  Furthermore, the generation unit 141 can generate a partial three-dimensional OCTA image by cutting out a depth range in an arbitrary retinal direction from the three-dimensional OCTA image. That is, the generation unit 141 can also generate a three-dimensional motion contrast image based on a predetermined range of motion contrast values in the depth direction of the subject as the OCTA image.

  Note that the depth range in an arbitrary retinal direction can be set by an examiner (operator). For example, the computer 140 displays candidates for selectable layers such as a layer from IS / OS to RPE and a layer from RPE to BM on the display unit 170. The inspector selects a predetermined layer from the displayed layer candidates. Then, the generation unit 141 performs integration in the depth direction of the retina in the layer selected by the examiner to generate a two-dimensional OCTA image (en-face blood vessel image) or a partial three-dimensional OCTA image. It is good.

  Further, the generation unit 141 may generate an OCTA image corresponding to a tomographic image from the motion contrast feature amount.

  The extracting unit 142 extracts, from the OCTA image generated by the generating unit 141, a blood vessel confluence portion-containing image region that is an image region including a blood vessel confluence portion in which at least two blood vessels merge to form one blood vessel. I do. The process of this extraction means 142 is demonstrated using FIG.

  FIG. 2 is a diagram illustrating an example of image region extraction processing by the extraction unit 142 of FIG. Specifically, in FIG. 2, the extraction unit 142 includes a blood vessel confluence portion including a blood vessel confluence portion in which at least two blood vessels merge from the OCTA image 200 generated by the generation unit 141 to form one blood vessel. An example in which image regions 210, 220, and 230 are extracted is shown.

  Thereafter, in the present embodiment, the generation unit 141 rescans the region of the fundus oculi Er of the eye E corresponding to the blood vessel merging portion-containing image region extracted by the extracting unit 142 to obtain the blood vessel merging portion-containing image region. Such an OCTA image is generated.

  FIG. 3 is a diagram illustrating an example of the OCTA image 300 related to the blood vessel merging portion-containing image region generated by the generation unit 141 of FIG. The OCTA image 300 shown in FIG. 3 is an OCTA image corresponding to the blood vessel confluence portion-containing image region 210 shown in FIG. Further, the OCTA image 300 shown in FIG. 3 is an image related to an image region including a blood vessel confluence portion (blood vessel confluence) 301 in which the two blood vessels 310 and 320 merge to form one blood vessel 330. Here, the blood vessel confluence portion (blood vessel confluence point) 301 is determined by, for example, the intersection of the center line of one blood vessel 310 and the center line of the other blood vessel 320 of the two blood vessels described above.

  The analyzing unit 143 analyzes the image related to the blood vessel merging portion-containing image region extracted by the extracting unit 142 (in this embodiment, the OCTA image related to the blood vessel merging portion-containing image region generated by the generating unit 141), In one blood vessel 330 shown in FIG. 3, laminar flow information relating to the laminar flow of blood flowing in from each of the two blood vessels 310 and 320 shown in FIG. 3 is acquired. Here, the analysis unit 143 acquires, for example, information including information on the length of the laminar flow in the blood flow direction of the blood vessel 330 illustrated in FIG. 3 as the laminar flow information. Moreover, the analysis means 143 is the ratio of the laminar flow of blood flowing in from the blood vessel 310 shown in FIG. 3 and the laminar flow of blood flowing in from the blood vessel 320 in the blood vessel 330 shown in FIG. Obtain information including laminar flow ratio information. Furthermore, the analysis unit 143 compares the laminar flow information with, for example, the blood vessel diameter ratio, which is the ratio of the blood vessel diameter of the blood vessel 310 and the blood vessel 320 shown in FIG. Get information including. Here, when acquiring the laminar flow information, the analysis unit 143 acquires a luminance profile from the OCTA image, and acquires the laminar flow information using the luminance profile. Hereinafter, the luminance profile used when the analysis unit 143 acquires the laminar flow information will be described.

  FIG. 4 is a diagram illustrating an example of a luminance profile acquired by the analysis unit 143 of FIG. Hereinafter, FIG. 4 will be described with reference to FIG.

  4A is a direction intersecting (for example, orthogonal to) the blood flow direction of the blood vessel 330 with the blood vessel confluence (blood vessel confluence) 301 shown in FIG. 3 as a reference, and the measurement point 302 and the measurement point 303 at both ends. An example of the luminance profile of the line segment is shown. In FIG. 4A, the horizontal axis represents the distance (number of pixels) from the measurement point 302 to the measurement point 303, and the vertical axis represents the luminance value (light / dark value). 4A shows the blood flow (laminar flow) of blood flowing from the blood vessel 310 and the blood of blood flowing from the blood vessel 320 that cross the line segment having the measurement point 302 and the measurement point 303 shown in FIG. Two luminance maximum values a1 and b1 indicating a flow (laminar flow) are shown. Specifically, FIG. 4A shows a first luminance maximum value a1 related to the blood flow (laminar flow) of blood flowing from the blood vessel 310 between 20 and 30 on the horizontal axis, and 55 on the horizontal axis. A second luminance maximum value b1 relating to the blood flow (laminar flow) of the blood flowing in from the blood vessel 320 between ˜65 is shown. At this point, the blood vessel confluence portion (blood vessel confluence point) 301 maintains the shape and laminar flow of red blood cells in the blood vessel, so FIG. 4A shows two blood vessels 310 and 320 in a single blood vessel 330. It means that two luminance maximum values a1 and b1 indicating the laminar flow of blood flowing in from each of these are observed. FIG. 4A shows a luminance minimum value c1 between the first luminance maximum value a1 and the second luminance maximum value b1, and the portion of this luminance minimum value c1 is shown in FIG. The OCTA image 300 shown is black, and it can be seen that there is no change (that is, a portion without blood flow).

  4B intersects the blood flow direction of the blood vessel 330 (for example, orthogonal) at a position moved 10 pixels downstream from the blood vessel confluence portion (blood vessel confluence point) 301 shown in FIG. An example of a luminance profile of a line segment that has a measurement point 304 and a measurement point 305 at both ends is shown. Also in FIG. 4B, the first luminance maximum value a2 related to the blood flow (laminar flow) of blood flowing from the blood vessel 310, and the second luminance maximum related to the blood flow (laminar flow) of blood flowing from the blood vessel 320. A value b2 and a luminance minimum value c2 between these luminance maximum values are shown.

  4C intersects with the blood flow direction of the blood vessel 330 at a position further moved downstream from the line segment having the measurement point 304 and the measurement point 305 shown in FIG. An example of a luminance profile of a line segment that is a direction orthogonal to each other and has the measurement point 306 and the measurement point 307 as both ends is shown. Also in FIG. 4C, the first luminance maximum value a3 related to the blood flow (laminar flow) of blood flowing from the blood vessel 310, and the second luminance maximum related to the blood flow (laminar flow) of blood flowing from the blood vessel 320. A value b3 and a luminance minimum value c3 between these luminance maximum values are shown.

  4D crosses the blood flow direction of the blood vessel 330 at a position further moved downstream from the line segment having the measurement points 306 and 307 shown in FIG. An example of a luminance profile of a line segment that is a direction orthogonal to each other and has the measurement point 308 and the measurement point 309 as both ends is shown. Also in FIG. 4D, the first luminance maximum value a4 related to the blood flow of blood flowing from the blood vessel 310, the second luminance maximum value b4 related to the blood flow of blood flowing from the blood vessel 320, and these luminance maximum values. The luminance minimum value c4 is slightly observed between them, but there is almost no difference. Therefore, in this embodiment, as a reference for determining that there is no laminar flow of blood flowing from each of the blood vessel 310 and the blood vessel 320 in the blood vessel 330, the luminance maximum value having the minimum luminance value (in FIG. The case where Ib / Ip ≧ 0.95 is adopted when the maximum value a4) is Ip and the luminance minimum value (in FIG. 4D, the luminance minimum value c4) is Ib. In general, since a single luminance peak is observed in a single blood vessel, the above-described determination criterion is adopted in which the luminance maximum value Ip and the luminance minimum value Ib are considered to be substantially the same. In the present embodiment, Ib / Ip ≧ 0.95 is adopted as a reference for determining that there is no laminar flow of blood flowing from each of the blood vessel 310 and the blood vessel 320 in the blood vessel 330. For example, adopting Ib / Ip ≧ 0.90 or employing other criteria is applicable to the present invention. That is, the “predetermined value” when Ib / Ip is equal to or greater than a predetermined value can be changed as appropriate.

  As described above, the analysis unit 143 acquires the laminar flow information by analyzing the luminance profile described with reference to FIG.

Here, it returns to description of FIG. 1 again.
The storage unit 144 stores various information, data, programs, and the like necessary for the computer 140 to perform various controls and processes. The storage unit 144 stores various information, data, and the like obtained by the computer 140 performing various controls and processes. For example, the storage unit 144 stores laminar flow information measured in the past for each eye E to be examined. Further, for example, the storage unit 144 stores a normal database (NDB) that is a database of normal eyes of each race, and normal eye laminar flow information is stored as one of the information. Shall.

  The display control unit 145 performs control to display the laminar flow information obtained by the analysis unit 143 on the display unit 170. Further, the display control unit 145 displays the OCTA image generated by the generation unit 141, various types of information obtained by the extraction unit 142 and the analysis unit 143, various types of information stored in the storage unit 144, and the like. Also controls to display on the screen.

  The display unit 170 displays various images and various information based on the control of the display control unit 145. The display unit 170 is a display such as a liquid crystal, for example. The display unit 170 includes a laminar flow information obtained by the analyzing unit 143, an OCTA image generated by the generating unit 141, and various types of information obtained by the extracting unit 142 and the analyzing unit 143 under the control of the display control unit 145. Information, various information stored in the storage means 144, and the like are displayed.

Next, a processing procedure in the control method of the ophthalmologic apparatus 100 will be described.
FIG. 5 is a flowchart illustrating an example of a processing procedure in the control method of the ophthalmologic apparatus 100 according to the embodiment of the present invention.

  For example, when an imaging instruction for the eye E is given from a user interface (not shown), the computer 140 (for example, the generation unit 141) reads out an interference signal that is an imaging signal from the interference light detection unit 130 in step S101. I do. At this time, in this step, data related to the interference signal that is read in advance from the interference light detection unit 130 and stored in the storage unit 144 as saved data may be read.

  Subsequently, in step S102, the generation unit 141 performs processing for generating the above-described OCTA image (for example, 200 in FIG. 2) based on the interference signal that is the imaging signal read out in step S101.

  Subsequently, in step S103, the extraction unit 142 determines whether or not the OCTA image generated in step S102 includes a blood vessel merge portion that combines at least two blood vessels together with the presence or absence of blood vessels to form one blood vessel. To do.

As a result of the determination in step S103, when the OCTA image generated in step S102 has a blood vessel and has a blood vessel merging portion (S103 / YES), the extraction unit 142 includes the blood vessel merging portion from the OCTA image. A blood vessel confluence portion-containing image region is extracted. Examples of the blood vessel confluence portion-containing image region extracted by the extraction unit 142 include blood vessel confluence portion-containing image regions 210, 220, and 230 shown in FIG. Thereafter, the process proceeds to step S104.
In step S104, the generation unit 141 rescans the region of the fundus Er of the eye E corresponding to the blood vessel merging portion-containing image region extracted by the extraction unit 142, and includes the vascular confluence portion. An OCTA image related to the image region is generated. An example of the OCTA image generated in this step is an OCTA image 300 shown in FIG. Here, in this step, in order to improve the analysis accuracy, in order to generate an OCTA image with higher resolution than the OCTA image generated in step S102, the fundus Er of the eye E to be examined corresponding to the blood vessel confluence portion-containing image region is generated. The area is rescanned at a specified interval (for example, 5 μm).

  Subsequently, in step S105, the analysis unit 143 obtains the position coordinates and the position coordinates of the blood vessel merging portion (blood vessel merging point) in which at least two blood vessels merge to form one blood vessel from the OCTA image generated in step S104. Perform the process. For example, the position coordinates of the blood vessel merging portion (blood vessel merging point) 301 shown in FIG. 3 are acquired. In the present embodiment, the OCTA image 300 is subjected to image processing, and for example, the intersection of the center line of the blood vessel 310 and the center line of the blood vessel 320 is acquired as the blood vessel confluence portion (blood vessel confluence point) 301. You may acquire based on the position instruct | indicated by the interface.

  Subsequently, in step S106, the analysis unit 143 performs processing for acquiring a luminance profile in the blood vessel merging portion (blood vessel merging point) for which the position coordinates have been acquired in step S106, from the OCTA image generated in step S104. Here, for example, the luminance of a line segment that intersects with the blood flow direction of the blood vessel 330 and has the measurement point 302 and the measurement point 303 as both ends with reference to the blood vessel confluence portion (blood vessel confluence) 301 shown in FIG. A profile (luminance profile shown in FIG. 4A) is acquired.

  Subsequently, in step S107, the analysis unit 143 determines whether or not there are two or more peaks (luminance maximum values) in the luminance profile acquired in step S106. For example, in the case of the luminance profile shown in FIG. 4A, since there are two or more luminance maximum values including the luminance maximum values a1 and b1, a positive determination is made in this step (S107 / YES). .

As a result of the determination in step S107, if there are two or more peaks (luminance maximum values) in the luminance profile acquired in step S106, the process proceeds to step S108.
In step S108, the analysis unit 143 analyzes the OCTA image generated in step S104 and obtains laminar flow information related to the laminar flow of blood flowing from each of the plurality of blood vessels before joining in the blood vessel after joining. Perform the acquisition process.

  FIG. 6 is a diagram for explaining the laminar flow information obtained by the analysis processing in step S108 of FIG. An OCTA image 600 shown in FIG. 6 is an enlarged image of the OCTA image 300 shown in FIG. 3. In FIG. 6, the same components as those shown in FIG. In step S108 of FIG. 5, the analysis unit 143, for example, information on the length 610 of the laminar flow in the blood flow direction of the blood vessel 330 shown in FIG. 6 or the layer of blood that has flowed from the blood vessel 310 in the blood vessel 330 shown in FIG. Information on the laminar flow ratio, which is the ratio between the flow width 621 and the laminar flow width 622 of blood flowing from the blood vessel 320, is acquired as laminar flow information. Furthermore, the analysis unit 143 calculates a blood vessel diameter ratio that is a ratio of the blood vessel diameter 623 of the blood vessel 310 and the blood vessel diameter 624 of the blood vessel 320 shown in FIG. 6, for example, and calculates the laminar flow ratio and the blood vessel diameter ratio described above. The compared comparison information is acquired as laminar flow information. Details of step S108 in FIG. 5 will be described later with reference to FIGS.

When the process of step S108 is completed, when a negative determination is made at step S107 (S107 / NO), or when a negative determination is made at step S103 (S103 / NO), the process proceeds to step S109.
In step S109, the display control unit 145 performs control to display the laminar flow information and the like obtained by the analysis processing in step S108 on the display unit 170 together with the OCTA image generated by the generation unit 141 as necessary. Do. Further, the display control means 145 also displays the blood vessel merging portion information including the presence / absence of the blood vessel and the blood vessel merging portion in step S103, the luminance profile acquired in step S106, the determination result information in step S107, and the like on the display unit 170. Control the display. Then, when the process of step S109 ends, the process of the flowchart shown in FIG. 5 ends.

  Next, two modes shown in FIGS. 7 and 8 will be described with respect to a detailed processing procedure in the analysis processing in step S108 of FIG.

First, the description of FIG. 7 will be given.
FIG. 7 is a flowchart illustrating an example of a detailed processing procedure according to aspect 1 in the analysis processing in step S108 of FIG. In FIG. 7, the aspect 1 in the analysis process of step S108 is illustrated as step S108-1. Specifically, the aspect 1 in the analysis process of step S108 is to acquire information on the length 610 of the laminar flow in the blood flow direction of the blood vessel 330 shown in FIG. 6 as the laminar flow information.

  When step S108-1 shown in FIG. 7 is started, first, in step S201, the analysis unit 143 reads the position coordinates of the blood vessel merging portion (blood vessel merging point) acquired in step S105.

  Subsequently, in step S202, the analysis unit 143 stores and stores the position coordinates of the blood vessel merging portion (blood vessel merging point) read out in step S201 in the storage unit 144.

  Subsequently, in step S203, the analysis unit 143 moves 10 pixels downstream from the position coordinate (initially the position coordinate of the blood vessel merging point) measured last time in the blood flow direction of the blood vessel 330 shown in FIG. Get brightness profile in coordinates. Here, for example, brightness profiles as shown in FIGS. 4B to 4D and the like are acquired.

  Subsequently, in step S204, the analysis unit 143 sets the luminance maximum value having the minimum luminance value (for example, the luminance maximum value a4 in FIG. 4D) as Ip from the luminance profile acquired in step S203, and sets the luminance maximum value. The brightness minimum value between them (for example, brightness minimum value c4 in FIG. 4D) is acquired as Ib.

  Subsequently, in step S205, the analysis unit 143 determines whether Ib / Ip ≧ 0.95. As a result of this determination, if Ib / Ip ≧ 0.95 is not satisfied (that is, Ib / Ip <0.95) (S205 / NO), the blood vessel 310 is obtained with the position coordinates obtained in step S203. Then, it is determined that the laminar flow of blood flowing in from each of the blood vessels 320 is still observed, and the process returns to step S203 to perform the processing after step S203.

On the other hand, if Ib / Ip ≧ 0.95 as a result of the determination in step S205 (S205 / YES), the process proceeds to step S206.
In step S206, the analysis unit 143 stores the position coordinates determined as Ib / Ip ≧ 0.95 in the storage unit 144. Here, the position coordinates determined as Ib / Ip ≧ 0.95 are the position coordinates of the laminar flow limit point 601 shown in FIG.

  Subsequently, in step S207, the analysis unit 143 stores the position coordinates of the laminar flow limit point 601 shown in FIG. 6 saved in step S206 and the position of the blood vessel confluence portion (blood vessel confluence) shown in FIG. 6 saved in step S202. From the coordinates, a laminar flow length 610 (also referred to as a laminar flow length l) shown in FIG. 6 is calculated. Here, in the example shown in FIG. 6, the laminar flow length 610 (laminar flow length 1) was measured at about 15 μm. When the process of step S207 ends, the process of the flowchart shown in FIG. 7 ends.

  In the process of the flowchart illustrated in FIG. 7, the example in which the luminance profile is acquired by moving 10 pixels in step S203 has been described. Measurement can be performed. Further, although the threshold value is set to 0.95 (95%) in the determination in step S205, the measurement can be similarly performed even if the value is an arbitrary value from the relationship of image noise or the like.

Next, FIG. 8 will be described.
FIG. 8 is a flowchart illustrating an example of a detailed processing procedure according to aspect 2 in the analysis processing in step S108 of FIG. In FIG. 8, the aspect 2 in the analysis process of step S108 is illustrated as step S108-2. Specifically, the aspect 2 in the analysis processing in step S108 is that the laminar flow information includes a laminar flow width 621 of blood flowing from the blood vessel 310 and a laminar flow width 622 of blood flowing from the blood vessel 320 shown in FIG. Information on the laminar flow ratio, which is the ratio, is acquired. Furthermore, as a modified example of the aspect 2 in the analysis processing of step S108, as the laminar flow information, the blood vessel diameter ratio that is the ratio of the blood vessel diameter 623 of the blood vessel 310 and the blood vessel diameter 624 of the blood vessel 320 shown in FIG. The comparison information obtained by comparing the flow ratio is acquired.

  When step S108-1 shown in FIG. 8 is started, first, in step S301, the analysis unit 143 reads the position coordinates of the blood vessel merging portion (blood vessel merging point) acquired in step S105.

  Subsequently, in step S302, the analysis unit 143 moves 10 pixels downstream from the position coordinate of the blood vessel merging portion (blood vessel merging point) in the blood flow direction of the blood vessel 330 shown in FIG. To get. Here, for example, the brightness profile shown in FIG.

  Subsequently, in step S303, the analysis unit 143 determines the width of the first luminance distribution in a mountain shape corresponding to the laminar flow of blood flowing in from one blood vessel 310 from the luminance profile acquired in step S302 (FIG. 4B). ) And the width of the mountain-shaped second luminance distribution corresponding to the laminar flow of blood flowing from the other blood vessel 320 (Fb shown in FIG. 4B). Here, the width Fa of the first luminance distribution can be regarded as the width 621 of the laminar flow of blood flowing from the blood vessel 310, and the width Fb of the second luminance distribution is the laminar flow of blood flowing from the blood vessel 320. Assume that the width 622 can be considered. Further, for example, in FIG. 4B, it is desirable that the widths Fa and Fb of the respective luminance distributions are full widths at half maximum (FWHM). However, since the position and intensity of the luminance minimum value c2 in FIG. 4B are values that are difficult to measure FWHM, the widths Fa and Fb of the respective luminance distributions are measured with reference to the position of the luminance minimum value c2. Yes.

  Subsequently, in step S304, the analysis unit 143 calculates a laminar flow ratio (Fa / Fb) represented by a ratio between the width Fa of the first luminance distribution and the width Fb of the second luminance distribution acquired in step S303. calculate. Thereafter, the analysis unit 143 stores the calculated laminar flow ratio (Fa / Fb) in the storage unit 144 and stores it. When the process of step S304 ends, the process of the flowchart shown in FIG. 8 ends.

  As a modified example of the aspect 2 in the analysis processing in step S108, first, the analysis unit 143 has the blood vessel diameter Da (623 shown in FIG. 6) of the blood vessel 310 before joining and the blood vessel diameter Db (FIG. 6) of the blood vessel 320 before joining. The blood vessel diameter ratio (Da / Db), which is a ratio to 624) shown in FIG. And the analysis means 143 acquires the comparison information which compared the laminar flow ratio (Fa / Fb) mentioned above and the blood vessel diameter ratio (Da / Db). By displaying this comparison information, it is possible to provide information that can be used for disease diagnosis of the eye E.

  Further, in the present embodiment, the display control unit 145 displays the past laminar flow information of the subject eye E stored in the storage unit 144 together with the laminar flow information of the subject eye E acquired by the analyzing unit 143. Control to display on 170 is also performed. By performing this display control, it is possible to perform the follow-up observation (function deterioration, etc.) of the eye E. In addition, when performing this follow-up observation, it is desirable to observe about the same conditions, a method, and the same location.

  In the present embodiment, the display control unit 145 displays the laminar flow information of the normal eye stored in the storage unit 144 together with the laminar flow information of the eye E acquired by the analyzing unit 143 on the display unit 170. Also controls. By performing this display control, it becomes possible to perform disease diagnosis (lifestyle-related diseases, etc.) of the eye E while comparing with normal eyes. When performing comparative observation with the normal eye, it is desirable to observe the same conditions, method, and the same location.

As described above, the ophthalmic apparatus 100 according to the present embodiment generates an OCTA image including the blood vessel of the eye E (S102 in FIG. 5), and at least two blood vessels 310 and 320 are included in the OCTA image. A blood vessel confluence portion-containing image region including a blood vessel confluence portion that is merged into one blood vessel 330 is extracted (S103 in FIG. 5), and an image related to the blood vessel confluence portion-containing image region is analyzed. And 320, the laminar flow information relating to the laminar flow of blood flowing in from each of them is acquired (S108 in FIG. 5), and the control for displaying the laminar flow information on the display unit 170 is performed (S109 in FIG. 5). .
According to such a configuration, since the laminar flow information of the blood flowing in the blood vessel of the eye E is acquired and displayed, the blood flow state of the eye E can be grasped, and as a result, the subject's blood flow Information that can be used for diagnosing the disease of the eye E can be provided to the user while minimizing the burden.

(Other embodiments)
In the above-described embodiment of the present invention, in order to improve the analysis accuracy, in step S104 in FIG. 5, re-scanning is performed to generate an OCTA image having a higher resolution than the OCTA image generated in step S102. Although the analysis processing is performed on the OCTA image obtained by scanning, the present invention is not limited to this configuration. For example, when the image quality of the OCTA image generated in step S102 of FIG. 5 is considered to be sufficient, the extraction unit 142 extracts from the OCTA image generated in step S102 in step S103 without performing the process in step S104. A form in which an analysis process is performed on the image of the blood vessel merging portion-containing image region can also be applied to the present invention. In step S104 of FIG. 5, the spot diameter of the light beam by the wavelength swept light source 110 at the time of rescanning may be changed in order to generate a higher resolution OCTA image. Further, at the time of re-scanning, it is desirable to scan perpendicularly to the blood flow direction with respect to the blood vessel 330 after joining.

  In the above-described embodiment of the present invention, the laminar flow information of the blood flowing in the blood vessel of the eye E is obtained using the OCTA image related to the fundus plane. However, the present invention is limited to this embodiment. is not. For example, a form of acquiring laminar flow information of blood flowing in the blood vessel of the eye E using an OCTA tomographic image (OCTA-B scan image) is also applicable to the present invention. In addition, laminar flow information of blood flowing in the blood vessel of the eye E may be acquired from a numerical value (graph or the like) instead of an image using original data (before and after signal processing) of an OCTA tomographic image.

  Further, in the above-described embodiment of the present invention, the blood vessel confluence portion (blood vessel confluence point) 301 is determined by the intersection of the center line of the blood vessel 310 and the center line of the blood vessel 320, but the present invention is limited to this form. However, other forms such as an intersection of blood vessel walls are also applicable. Furthermore, the apparatus, control method, and program according to the embodiments of the present invention are not necessarily limited to the apparatus related to ophthalmology, the control method, and the program thereof. As the blood vessel-containing image, in addition to the image relating to the eye to be examined, a blood vessel image included in the breast or heart of the subject can be targeted. Blood vessel images of various parts of the subject can be captured by using, for example, ultrasonic waves or photoacoustic waves.

In the embodiment of the present invention described above, an example in which an OCTA image is applied as a blood vessel-containing image including a blood vessel of the eye E has been described. However, the present invention is not limited to this embodiment. For example, a form in which a fundus image obtained by a fluorescence fundus imaging method or an SLO image (Scanning Laser Ophthalmoscope) is applied as a blood vessel-containing image including a blood vessel of the eye E is also applicable to the present invention.
FIG. 9 is a diagram illustrating an embodiment in which the fundus image obtained by the fluorescence fundus imaging method is applied as a blood vessel-containing image including a blood vessel of the eye E according to the embodiment of the present invention. In the case of the example shown in FIG. 9, a form in which the blood vessel confluence portion-containing image region 910 is extracted from the fundus image 900 obtained by the fluorescence fundus imaging method and the above-described analysis processing is performed.

The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.
This program and a computer-readable storage medium storing the program are included in the present invention.

  Note that the above-described embodiments of the present invention are merely examples of implementation in practicing the present invention, and the technical scope of the present invention should not be construed as being limited thereto. It is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

DESCRIPTION OF SYMBOLS 100: Ophthalmology apparatus, 110: Wavelength sweep light source, 120: Optical signal branching / multiplexing unit, 130 Interference light detection unit, 140: Computer, 141: Generation unit, 142: Extraction unit, 143: Analysis unit, 144: Storage unit 145: display control means, 150: measurement arm, 160: reference arm, 170: display unit, E: eye to be examined, Ef: fundus

Claims (18)

Generating means for generating a blood vessel-containing image including blood vessels of the eye to be examined;
An extracting means for extracting an image region including a blood vessel confluence portion in which at least two blood vessels merge to form one blood vessel from the blood vessel-containing image;
Analyzing the image related to the image region, and obtaining laminar flow information related to the laminar flow of blood flowing from each of the two blood vessels in the one blood vessel;
An ophthalmologic apparatus comprising: display control means for performing control to display the laminar flow information on a display unit.   The ophthalmic apparatus according to claim 1, wherein the analysis unit acquires information including information on a length of the laminar flow in a blood flow direction of the one blood vessel as the laminar flow information.   The analysis unit acquires a luminance profile in a direction intersecting the blood flow direction from an image related to the image region, and acquires information on the length of the laminar flow using the luminance profile. Item 3. The ophthalmic apparatus according to Item 2.   The analysis means includes a first luminance maximum value corresponding to a laminar flow of blood flowing from one of the two blood vessels, and an inflow from the other blood vessel of the two blood vessels. Obtaining a second luminance maximum value corresponding to the laminar flow of the blood and a luminance minimum value between the first luminance maximum value and the second luminance maximum value, and obtaining the first luminance maximum value. The ophthalmologic apparatus according to claim 3, wherein information on the length of the laminar flow is acquired using the second luminance maximum value and the luminance minimum value.   The analyzing means is configured to detect the laminar flow according to a ratio value between a luminance maximum value having a smaller luminance value of the first luminance maximum value and the second luminance maximum value and the luminance minimum value. The ophthalmic apparatus according to claim 4, wherein length information is acquired.   The analysis unit calculates a value of the ratio of the luminance minimum value to the luminance maximum value as the value of the ratio, and acquires the luminance profile at which the value of the ratio is equal to or greater than a predetermined value and the blood vessel merging unit The ophthalmologic apparatus according to claim 5, wherein information on the length of the laminar flow is acquired according to a length of the position of the laminar flow.   The analysis means includes, as the laminar flow information, a laminar flow of blood flowing from one of the two blood vessels and blood flowing from the other blood vessel of the two blood vessels in the one blood vessel. The ophthalmic apparatus according to claim 1, wherein information including information on a laminar flow ratio, which is a ratio with a laminar flow, is acquired.   The analysis unit acquires a luminance profile in a direction intersecting a blood flow direction of the one blood vessel from an image related to the image region, and acquires information on the laminar flow ratio using the luminance profile. The ophthalmic apparatus according to claim 7.   The analyzing means determines, from the luminance profile, a width of a mountain-shaped first luminance distribution corresponding to a laminar flow of blood flowing from one of the two blood vessels, and the other of the two blood vessels. And the width of the second luminance distribution in the shape of a mountain corresponding to the laminar flow of blood flowing in from the blood vessel, and the ratio value between the width of the first luminance distribution and the width of the second luminance distribution. 9. The ophthalmologic apparatus according to claim 8, wherein information on the laminar flow ratio is acquired accordingly. The analysis means includes
Obtaining a blood vessel diameter of each of the two blood vessels and calculating a blood vessel diameter ratio that is a ratio of the respective blood vessel diameters;
The ophthalmologic apparatus according to claim 7, wherein information including comparison information obtained by comparing the laminar flow ratio and the blood vessel diameter ratio is acquired as the laminar flow information.   11. The ophthalmologic apparatus according to claim 1, wherein the blood vessel-containing image is an OCT angiography image, a fundus image obtained by fluorescence fundus imaging, or an SLO image. The generating means further generates an image including the blood vessel merging portion of the eye to be examined corresponding to the image region as an image related to the image region,
The ophthalmologic according to any one of claims 1 to 11, wherein the analysis unit analyzes the image including the blood vessel merging portion generated by the generation unit, and acquires the laminar flow information. apparatus. A storage means for storing the past laminar flow information of the eye to be examined;
The said display control means performs control which displays the past laminar flow information memorize | stored in the said memory | storage means on the said display part with the laminar flow information acquired by the said analysis means. The ophthalmic apparatus according to any one of the above. A storage means for storing the laminar flow information of the normal eye;
The said display control means performs control which displays the laminar flow information of the normal eye memorize | stored in the said memory | storage means on the said display part with the laminar flow information acquired by the said analysis means. The ophthalmologic apparatus according to any one of 13. Generating a blood vessel-containing image including blood vessels;
An extraction step of extracting an image region including a blood vessel confluence portion in which at least two blood vessels merge to form one blood vessel from the blood vessel-containing image;
An analysis step of analyzing an image related to the image region and acquiring laminar flow information related to a laminar flow of blood flowing from each of the two blood vessels in the one blood vessel;
A display control step of performing control to display the laminar flow information on a display unit.   The apparatus control method according to claim 15, wherein the blood vessel-containing image is an image including a blood vessel of an eye to be examined. Generating a blood vessel-containing image including blood vessels;
An extraction step of extracting an image region including a blood vessel confluence portion in which at least two blood vessels merge to form one blood vessel from the blood vessel-containing image;
An analysis step of analyzing an image related to the image region and acquiring laminar flow information related to a laminar flow of blood flowing from each of the two blood vessels in the one blood vessel;
And a display control step for controlling the display of the laminar flow information on a display unit.   The program according to claim 17, wherein the blood vessel-containing image is an image including a blood vessel of an eye to be examined.